1. Field of the Invention
The present invention relates to an image capturing device and an image capturing method for forming a color image of an object using an infrared beam reflected by the object or an infrared beam radiated by the object, and so on.
2. Description of the Related Art
Conventionally, as a method for forming a color image of an object by irradiating an infrared beam onto the object, a pseudo-color scale indication has been used. Namely, An intensity level of an intensity distribution of an infrared beam, which is obtained from an infrared beam reflected by the object, is divided into a plurality of intensity levels, and by assigning a proper color to each intensity level interval, a color image is formed and the color image is displayed as an infrared color image of the object.
However, although the pseudo-color scale indication is effective for use of extracting a certain intensity level in comparison with the gray scale indication (monochromatic indication), which indicates an image with density of gray color, and the monochromatic color scale indication, which indicates an image with density of a mono-color or a primary color, conversely, there are a lot of cases where the image becomes unnatural and hard to look because image data is not increased.
On the other hand, in the field of astronomy, conventionally, using a plurality of infrared band-pass filters to infrared beams irradiated by fixed stars and nebulas, a plurality of infrared images are formed, and a method of coloring each of the infrared images with proper and a plurality of colors and forming a synthetic color image has been performed.
However, there are a lot of cases where this synthetic color image is hard to look because this synthetic color image is colored, being not related to an image by a visible light. And, it is not able to capture satellites, etc. which do not radiate infrared.
On the other hand, conventionally, by composing a monochromatic infrared photograph and a normal visible light photograph, forming a synthetic color photograph has been also performed.
However, this synthetic color photograph is not related to real colors. Therefore, seemingly it is fantastic or artistic, but it looks unnatural because it is not real and it is photographed only at a daytime with the sun-beam.
On the other hand, a color still image capturing device is proposed, which includes a monochromatic video camera, a light source which radiates red, blue, and green lights, a control circuit which controls so as to emit red, blue, and green lights from the light source sequentially, and a capturing synthetic circuit which sequentially captures output video signals of the video camera when the light source radiates the red, the blue, and the green lights (for example, reference: Japanese Patent laid-open publication No. Tokkaihei 08-65690).
However, the color still image capturing device of Japanese Patent laid-open publication No. Tokkaihei 08-65690 is a device related to a visible light region but is not intended for infrared beams. And, the color still image capturing device of Japanese Patent laid-open publication No. Tokkaihei 08-65690 is a device which composes colors by additive mixture color with the same colors as colors of visible lights radiated, therefore, at least at this point, it is different from following disclosed one aspect of the present invention and one embodiment of the present invention.
On the other hand, an X-ray CT scanning device is proposed which includes an X-ray source generating X-ray, a two-dimensional X-ray detector detecting an X-ray transmitted through an inspected body, and a patient bed, where the X-ray source can turn consecutively with a synchronization with the movement of the patient bed and can scan the inspected body spirally, the X-ray CT scanning device having a energy conversion means which can change energy properties of an X-ray irradiated onto an object along a slice direction, and by scanning spirally using the energy conversion means, the device being capable of measuring at a same slice position by X-ray having a plurality of and different effective energies, and by extrapolating obtained data among data measured with a same effective energy, and it is possible to obtain an image having an arbitrary effective energy and an difference between images having an arbitrary effective energy (for example, reference: Japanese Patent laid-open publication No. Tokkai 2004-236915).
However, the X-ray CT scanning device of Japanese Patent laid-open publication No. Tokkai 2004-236915 is a device related to an X-ray region, but is not intended for infrared beams. And, the X-ray CT scanning device of Japanese Patent laid-open publication No. Tokkai 2004-236915 is an X-ray transmission image capturing device, which is different from the present invention. Furthermore, a color synthetic image by the X-ray CT scanning device of Japanese Patent laid-open publication No. Tokkai 2004-236915 is colored so as to improve visibility and is quite different coloring from nature, therefore, at least at this point, the X-ray CT scanning device is different from the following disclosure of one aspect of the present invention and one embodiment of the present invention.
On the other hand, a wavelength selecting type liquid crystal camera device is proposed which sets a light image obtained by capturing operation as a light image at each wavelength region and extracts a specific object image, including a liquid crystal filter which has an optical band pass filter function, and can change the center wavelength by voltage, an imaging device which photo-electrically changes a light image at a wavelength region selected by this liquid crystal filter and generates a video signal, and an image calculating part which calculates a signal level difference between two images having different wavelengths output from this imaging device, and generates a video signal based on an absolute value of this difference (for example, Japanese Patent laid-open publication No. Tokkai 2000-152254).
However, the wavelength selecting type liquid crystal filter of Japanese Patent laid-open publication No. Tokkai 2000-152254 is a device which can transmit only one wavelength region, but is not equivalent to the present invention. And the wavelength selecting type liquid crystal camera device of Japanese Patent laid-open publication No. Tokkai 2000-152254 is a device which is intended to improve visibility by detecting a signal level difference between two images having different wavelengths and by imaging, therefore, at least at this point, the wavelength selecting type liquid crystal camera device is different from following disclosed one aspect of the present invention and one embodiment of the present invention.
In addition, in Japanese Patent laid-open publication No. Tokkai 2000-152254, a wavelength selecting type liquid crystal camera device is also proposed which sets a light image obtained by capturing operation as a light image at each wavelength region and extracts a specific object image, including a liquid crystal filter which has an optical band pass filter function, and which is capable of changing the center wavelength by voltage, a color imaging device which separates a light image at each wavelength region selected by this liquid crystal filter into red (R), green (G), and blue (B) regions, photo-electrically changes, and generates a R color video signal, a G color video signal, and a B color video signal, wherein the wavelength selecting type liquid crystal camera calculates a signal level difference about each pixel having a same spatial coordinate to each of R color, G color, and B color about R color video signal, G color video signal, and B color video signal output from this color imaging device, and generates R color video signal, G color video signal, and B color video signal based on an absolute value of this difference, and a color video signal composing part which composes R color video signal, G color video signal, and B color video signal output from this color imaging device and generates a synthetic color video signal.
However, this liquid crystal filter of Japanese Patent laid-open publication No. Tokkai 2000-152254 is a device which separates a light image into a red (R) region, a green (G) region, and a blue (B) region, and the light is intended for a visible region, therefore, at least at this point, the wavelength selecting type liquid crystal camera device is different from following disclosure of one aspect of the present invention and one embodiment of the present invention.
On the other hand, an infrared color image forming device is proposed, which includes an infrared camera which detects an infrared beam radiating or reflected from an object and obtains infrared spectrum image, a memory device which beforehand memorizes correspondence data between a color and an infrared spectrum radiating intensity or an infrared spectrum reflectivity about the object, a first processing means which decides a color at each position of the infrared spectrum image from a value of an infrared spectrum radiating intensity or an infrared spectrum reflectivity at each position of the infrared spectrum image based on the correspondence data, and a second processing means which synthetically colors at each position of an image of the object based on a color data obtained by the first processing means (for example, reference: Japanese Patent laid-open publication No. Tokkai 2002-171519).
However, the infrared color image forming device of Japanese Patent laid-open publication No. Tokkai 2002-171519 requires a measurement and a preparation of correspondence data between a real color of an object and an infrared spectrum radiating intensity or an infrared spectrum reflectivity beforehand, therefore, a prior minute visible and infrared spectrum measurement of the object is essential. Such correspondence data requires a memory device which memorizes the correspondence data and time, at least at this point, the infrared color image forming device is different from the present invention which does not need coloring based on comparison with correspondence data.
On the other hand, a night vision color camera is proposed, which is characterized by irradiating an infrared beam and a ultraviolet beams onto an object and by outputting a color image signal by judging a color from an infrared beam image signal obtained by capturing the object and an ultraviolet beam image signal (for example, reference: Japanese Patent laid-open publication No. Tokkai 2001-36916 and Japanese Patent laid-open publication No. Tokkai 2005-45559).
However, the night vision color camera of Japanese Patent laid-open publication No. Tokkai 2001-36916 is a camera which needs irradiating an ultraviolet beam, therefore, the present invention is different at least at a point where the present invention does not need such an ultraviolet irradiation.
On the other hand, an infrared capturing device is proposed, which includes plural optical filters which selectively transmit or reflect infrared wavelength regions which are different each other in an optical system, a plurality of capturing means which capture each infrared light image obtained by a plurality of optical filters, and a signal processing means which forms an image data from an image signal obtained by plural capturing means (for example, reference: Japanese Patent laid-open publication No. Tokkaisho 62-208784).
However, the infrared capturing device of Japanese Patent laid-open publication No. Tokkaisho 62-208784 is an image capturing device which is only for infrared beams and a relation with image capturing under a visible light is not mentioned. And, coloring, which is totally unrelated to an image by a visible light, is performed. Moreover, it is not able to capture an object, etc. which do not radiate infrared beams. In other words, reappearing color of an object under a visible light by capturing with an infrared irradiation is not disclosed.
On the other hand, an infrared image capturing device is proposed, which is characterized by displaying an infrared image on a color display, and by displaying output signals from infrared detectors having different detecting wavelengths, the signals corresponding to different dies, on a display (for example, reference: Japanese Patent laid-open publication No. Tokkaihei 04-86075).
However, the infrared image capturing device of Japanese Patent laid-open publication No. Tokkaihei 04-86075 is an image capturing device which is only for an infrared beam and a relation to an image capturing under a visible light is not described. And, the coloring is totally unrelated to an image by a visible light. Moreover, it is not able to capture an object, etc. which do not radiate infrared beams. It is not disclosed to reappear color of an object under a visible light by irradiating an infrared beam.
On the other hand, an infrared image capturing device is proposed, which is an infrared image capturing device including an infrared beam light source having a radiation distribution at an infrared region, an image capturing lens, a CCD sensor where light receiving elements having a light receiving sensitivity at an infrared region and a visible region are placed in a shape of a matrix, a plurality of color filters each of which transmits a visible light at a specific wavelength region and an infrared beam at a specific wavelength region and which is characterized by comprising an infrared transmitting filter which transmits an infrared beam excluding a visible light, an image capturing signal forming means which generates an image signal based on a light incidence of an infrared beam into the image sensor, a digital conversion means which converts the image capturing signal into digital signal, and a memory which temporarily maintains a digital signal converted by the digital conversion means (for example, reference: Japanese Patent laid-open publication No. Tokkai 2006-109120).
However, the infrared image capturing device of Japanese Patent laid-open publication No. Tokkai 2006-109120 needs an infrared transmitting filter which transmits an infrared beam excluding a visible light.
On the other hand, an image capturing device is proposed, which includes an image capturing means which captures an object, generates a plurality of color signals based on a visible light component and generates an infrared beam brightness signal based on an infrared component from the object, and a color image generating means which generates a color image based on each color signal generated by the image capturing means and an infrared beam brightness signal (for example, reference: Japanese Patent laid-open publication No. Tokkai 2006-148690).
However, the image capturing device of Japanese Patent laid-open publication No. Tokkai 2006-148690 is a device which captures an image by synthesizing an image under a visible light and an image under a infrared beam, so has a difficulty in a color image capturing under a darkness.
On the other hand, a method for improving an eyesight in a car, in particular, during a night time, at a bad weather, or at fog, where an image of a current traffic scene is captured by a camera reacting at an outside region of a visible spectrum, and the image is reappeared by a visible spectrum using an optical system displaying device in a car, is proposed, which is characterized by automatically distinguishing a type of an object included in a traffic scene captured by a camera and by indicating an object distinguished depending on a type on an optical system displaying device by a brightness and/or color corresponding to a typical brightness and/or color which is had by the object under a day light (for example, reference: Japanese Patent laid-open publication No. Tokkai 2003-78908).
However, the means and the device improving view in a car of Japanese Patent laid-open publication No. Tokkai 2003-78908 have a problem where a burden of image processing becomes very large because type of all objects included in a video image must be distinguished. And, there is sense of incongruity because of display by monochromatic or pseudo-color with mono-colors.
On the other hand, an endoscope device is proposed, which is characterized by including an illuminating means which is cable of illuminating an illuminating light which includes a white illuminating light in a visible light region and an illuminating light including a light in a wavelength region except a visible light region onto an object selectively, and a plurality of kinds of filters which transmit lights in different wavelength regions in a visible light region, and, where the filters are mosaic-filters having plural transmitting property which also transmit a light in a wavelength region more than a visible light region, further including a solid state image capturing device which captures an image of an object illuminated by the illuminating means, the mosaic-filter being put on a receiving surface, and a means obtaining a color image by assigning a desired color corresponding to each kind of filter of the mosaic-filter, to each image element of an image corresponding to an output signal which read out from the solid state image capturing device by capturing an image of the object (for example, reference: Japanese Patent laid-open publication No. Tokkaihei 04-357926).
However, the endoscope device of Japanese Patent laid-open publication No. Tokkaihei 04-357926 is a device which is cable of detecting color differences of each part of an object which is difficult to distinguish by a normal image in a visible region and displaying by pseudo-color, where it is not disclosed to reappear color of an object under a visible light by capturing an image with an infrared irradiation.
On the other hand, a system which is cable of measuring chromaticity in a visible and an invisible regions is proposed, which is characterized by including, at least, a spectrum optical part which receives a radiation light in all wavelength region which is radiated from an object sample, and which makes the radiation light into a spectrum of elemental lights of n units (n>=3) having different center wavelength each other, a photoelectric conversion part which converts each of the element lights of n unit photo-electrically, and generates each of electric signals of n unit which correspond to the element lights of n unit, respectively, an image processing part which, by processing the electric signals of n unit, performs a generation of a pseudo-color image of the sample and a calculation of a number value which is defined based on a coloring system for doing color display of the pseudo-color image, and an image outputting part which output the pseudo-color image and/or the number value, where the image processing part comprises, at least, an image signal generation processing means which, by independently applying each of sensitivity function of m units (m>=3) against one signal group comprising the electric signals of n unit, generates pseudo-color basic image signals of m unit corresponding to each sensitivity function, a vector conversion processing means which, by applying matrix M to the pseudo-color basic image signals of m units and performing vector conversion, generates three pseudo-color image signals, an image formation processing means which composes the three pseudo-color image signals and generates the pseudo-color image, and a color processing means which calculates the number value defined based on the color system using the three pseudo-color image signals, where the sensitivity function of m units which is determined based on a correlation between a difference, which should be observed, of a physical condition or a chemical condition forming between each object which composes object group which the object sample belongs and a difference of a waveform forming between optical spectrum of each object which composes the object group, and where the matrix M is a matrix for approaching a most suitable sensitivity property and is, as a result, determined a color reproduction error forming at a time of generating the three pseudo-color image signals so as to become minimal (for example, reference: Japanese Patent laid-open publication No. Tokkai 2004-77143).
However, the system which is cable of measuring chromaticity in a visible and an invisible regions of Japanese Patent laid-open publication No. Tokkai 2004-77143 is a system which evaluates a desired information which is intended to be obtained from object sample by comparing with a standard sample, using an invisible color value and a color indication of a pseudo-color image, and which needs a preparation of a standard sample, and it is necessary to make a spectrum minutely in a wide wavelength range, therefore, there is a problem where a burden of image processing becomes very large.